Two-dimensional CdS/SnS₂ heterostructure: a highly efficient direct Z-scheme water splitting photocatalyst

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Efficient photocatalysts are crucial for overall water splitting without sacrificial agents.
• Existing photocatalysts often struggle with light absorption and charge carrier separation.

Purpose of the Study:

• To investigate a two-dimensional CdS/SnS2 heterostructure (CSHS) as a potential photocatalyst for water splitting.
• To explore the role of sulfur vacancies in enhancing photocatalytic activity.

Main Methods:

• First-principles calculations were employed to study the electronic and optical properties of the CSHS.
• The band alignment, charge carrier separation, and reaction pathways were analyzed.

Main Results:

• The CSHS exhibits enhanced visible and infrared light absorption.
• A type-II band alignment and built-in electric field facilitate efficient charge separation.
• The CSHS functions as a direct Z-scheme system for hydrogen and oxygen evolution.
• Sulfur vacancies in SnS2 reduce the oxygen evolution overpotential, enabling spontaneous water splitting.

Conclusions:

• The CdS/SnS2 heterostructure is a promising material for efficient photocatalytic water splitting.
• The design strategy of incorporating vacancies offers a pathway for developing advanced photocatalysts.